The present invention generally relates to exercise devices and, in particular, treadmills and incline trainers.
U.S. Pat. No. 5,944,635, incorporated by reference herein in its entirety, is an example of treadmill having a safety shutdown and latch off. U.S. Pat. No. 5,944,635 is invented by the inventor of this application and has been assigned to Digital Concepts of Missouri, Inc., the assignee of this application.
The incline trainer is an example of one type of treadmill which allows for a very steep incline (e.g. 30% or more). Such products present at least two safety conditions related to emergency stops and/or loss of AC line power. When an emergency stop condition occurs, the power stage should to be disabled for safety. Several specifications require this. In addition, when the AC line voltage drops out for any reason, the power stage should also be disabled. If either condition occurs and the user is operating the treadmill at a high incline (e.g., above 15%), the belt can run away and rotate in reverse since the motor controller alone can no longer provide resistance or a braking action to slow the belt.